PHP Doctrine: Custom nested set?

Question

Is it possible to have nested set capabilities in this somewhat custom setup?

Consider these 4 tables:

1. Object : ( oid , name ) contains: [1, 'Licence'] and [2, 'Exemption']
2. Licence : ( lid , name )
3. Exemption : ( eid , name )
4. Cost : ( oid , oid_ref , cost_oid , cost_oid_ref )

For:
P = Licence with lid [1]
R = Exemption with eid [2]

i can say "object P is a parent to object R " if the following Cost record exists:

[oid: 2 oid_ref: 2 cost_oid: 1 cost_oid_ref: 1]

I understand that this creates somesort of 'conditional foreign key' relation which I need to define in code. Is it possible to have the nested set loaded with these conditions?

Answer 1

我正在尝试使用column_aggregation继承进行某种方式，但是我有一种直觉，认为它行不通...：S